tl;dr - “bad blood”. The SMT developer (one guy, “Tools”) sold it to ZipoApps who immediately injected ads into the Play Store versions of all the tools and invented a name “Simple Mobile Tool” (note no “s”) which angered a lot of people. There were blogs and news articles and discussions, you just missed them which happens - it’s a period of transition in a difficult time.
Having participated lightly in the Github conversations, the community members who forked it took a lot of care to choose a new name (held several polls, etc.) and carefully constructed their presence in a positive manner without throwing any shade at the original developer or adware company who he sold it all to - they chose to take the noble route and just present their work without any vitriol or nastiness. They released Gallery first awhile ago, these are new updates and more apps being added - I saw changelog notes where they’re removing license-encumbered libraries and stuff like that which somehow flew under the radar on F-Droid.
